topic Snapmirror Cascade Reversal in ONTAP Discussions

Snapmirror Cascade Reversal

cshenberger — Wed, 04 Jun 2025 18:25:27 GMT

I have a snapmirror cascade A --> B --> C

I need to run a test of this where the site containing A and B is down and I want to run on the C copy, then when the site with A and B is fixed reverse the sync.

If I update, quiesce , then break the B --> C mirror then I can use the C to write data. However then when I try operations reverse resync i get message the the volume is part of a cascade and to delete the other snapmirrors

How can I reverse the copy so that A becomes the primary again without a full copy of the data again.

Re: Snapmirror Cascade Reversal

aborzenkov — Tue, 01 Nov 2016 18:30:06 GMT

Not sure I understand why you try to reverse anything. Just resync from B to C to continue replication.

Re: Snapmirror Cascade Reversal

cshenberger — Wed, 02 Nov 2016 10:46:43 GMT

I have to reverse because I need to keep the data that is written while C is the primary copy

Re: Snapmirror Cascade Reversal

aborzenkov — Wed, 02 Nov 2016 12:09:54 GMT

Break mirrors, setup in reverse direction, resync from C to B and then from B to A. As long as there is commmon snapshot resync will transfer only changes relative to it.